Intensity of Illumination « Various Distances

Aims:

· Arrange your materials as shown in the picture.

·

lux meter

Measure the intensity of illumination at various distances between lamp and lux meter. Connect the lux meter with the lower sockets of the digital multi-meter. Use the DC-range of 2 mA. Point your lux meter with its front side (red dot) at the source of light. The photosensitive spot of the lux meter should be placed on the virtual line connecting the numbers on the sheet (See the picture above!). Fill in the table. (Be careful with the units!) Take the calibration curve and find out the corresponding amounts of illumination strength in lx (lux).

distance

in cm

photocurrent

in mA

intensity of illumination in lx

· Draw a graph based on the data in your table. Examine and interpret the graph.

List of Materials:

· one experimental pad

· one lux meter

· one digital multi-meter

· one calibration curve

· one lamp

· one transformator